Skate sharpening device

ABSTRACT

An automatic skate sharpener comprises a skate sharpening mechanism inside a cover. A skate loading device is pivotally mounted in an opening in the protective cover, so that it can be pivoted between a loading position, in which the skate is on the outside of the protective cover, and a starting position for sharpening of a skate, in which the skate is on the inside of the protective cover. The skate loading device comprises a gripping device for releasably gripping at least one skate to be sharpened, first obturation device which substantially closes the opening in the skate loading position, and second obturation device which substantially closes the opening in the starting position.

TECHNICAL FIELD

The present invention relates to devices and machines for skatesharpening and especially to all-automatic devices and machines of thiskind.

BACKGROUND OF THE INVENTION

Skating has become increasingly popular, i.a. thanks to the greatincrease of the number of artificially frozen ice-hockey rinks andskating arenas. In connection therewith also the need of sharpening ofthe skates has increased considerably. At the same time the requirementsof the quality of the sharpening have increased, e.g. as regardsice-hockey and figure skates.

At present, almost all sharpening of skates is performed manually orsemi-automatically, the skates being braced in a jig or the like and arotating grinding wheel being passed over the skate blade a desirednumber of times. Not only the manual, but also the semi-automaticsharpening method requires a certain sharpening skill of the operator,and the sharpening procedure is time-consuming.

There is thus a great need of fully automated skate sharpening machines,which do not require any skilled operator but can be used by anybody,and which provide for a rapid sharpening of high quality. As far as weknow there is no all-automatic skate sharpening machine on the Swedishmarket, but there are several proposals for such machines in the patentliterature, e.g. in U.S. Pat. Nos. 2,438,543, 3,735,533, 3,827,185 and4,235,050. These previously disclosed automatic skate sharpeningmachines have deficiences in various respects, and the present inventionrelates to improvements, simplifications and developments of the knownskate sharpening devices.

OBJECT OF THE INVENTION

It is an object of the invention to provide an improved, simplified andsafer device for the loading of skates into all-automatic skatesharpening machines.

Another object of the invention is to provide for simplified sensing ofthe skate length, with consequent simplification of the mechanisms forgripping the skate and guiding the same when passing the grinding wheelduring the sharpening process.

A further object of the invention is to provide an all-automatic skatesharpening machine, which has a simple, rugged and reliable design, isvery simple to use and meets high demands as regards the quality of thesharpening.

These and other objects of the invention, which will becomeevident--directly or indirectly--from the following description ofpreferred embodiments, are achieved in that the skate sharpening deviceshave been given the characteristics indicated in the appended claims.

SHORT DESCRIPTION OF THE DRAWINGS

The enclosed drawings shown the following:

FIG. 1 is a schematic oblique front perspective view of a preferredembodiment of an automated skate sharpening machine according to theinvention.

FIG. 2 is a first side elevational view of the skate sharpening machineshown in FIG. 1, the side wall having been removed.

FIG. 3 is a side elevational view corresponding to FIG. 2 and showingthe opposite side of the skate sharpening machine.

FIG. 4 is a rear view of the skate sharpening machine according to FIGS.1-3, the rear wall having been removed.

FIGS. 5 and 6 are perspective views of a skate loading device accordingto the invention forming part of the skate sharpening machine shown inFIGS. 1-4, viewed from the inside of the machine and shown in theloading position and in the starting position for sharpeningrespectively.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 substantially shows the front of a preferred embodiment of askate sharpening machine according to the invention, i.e. the sidefacing the user. The skate sharpening machine is generally designated bythe reference numeral 1 and its front wall is designated 1a. Althoughonly the front wall 1a is shown in the drawings, it is to be understoodthat also the other sides of the skate sharpening machine (the top andbottom sides included) in use are covered with robust cover platespreventing the user from getting access to the inside of the skatesharpening machine. On the front wall 1a there is shown a skate loadingdevice 2 having a schematically shown skate 3 inserted therein. The mainfunction of the loading device 2 is to feed the skate 3 to be sharpenedfrom the loading position outside the skate sharpening machine 1, asshown in FIG. 1, to a correct starting position for sharpening insidethe machine. The loading device 2 is an essential part of the skatesharpening machine 1 and will be described in detail below, especiallywith reference to FIGS. 5 and 6.

On the front wall 1a there is also a control and indicator panel 4,which in the shown embodiment comprises an instruction text window 5,function selector buttons 6, slots 7 for inserting coins, and/or a slot8 for receiving credit cards, account cards, payment cards or the like.The functions of the control and indicator panel 4 are basically toreceive the customer's payment through the coin slots 7 or the card slot8, to give instructions to the customer through the text window 5, andto receive the customer's selection as regards type of grinding, etc.through the selector buttons 6. The latter can, for example, give theclient the possibility to select the desired skate type (such asice-hockey or figure skates), the desired degree of sharpening (such asone or two sharpening cycles), etc.

The text window 5 displaces relevant information and instructions to thecustomer (or service personnel), for example indicating that the machineis occupied, informing about ongoing working moments, instructing abouthow and when to pay, select the desired skate type and the degree ofsharpening, insert a skate into or remove a skate from the loadingdevice 2, producing error messages, etc. The coin slots 7, the cardsensor 8, the selector buttons 6 and the text window 5 all representtechnology which is well known per se in connection with different typesof automats and will therefore not be described any further herein.

In the previously known automatic skate sharpening machines referred toabove the skates are loaded into the machine from the top side andplaced directly into the jaws or the like keeping the skate clampedduring the sharpening operation. It is often required that the customerperform further working moments, such as positioning slide piecesagainst the front and rear edges of the skate in order to determine thelength and position of the skate. Such a design gives the customeraccess to the interior mechanisms of the machine. This in turn creates arisk for damages both on the customer and the machine, necessitatingcomplex mechanisms for closing the machine when the skate has beenpositioned.

As is best seen from FIGS. 5 and 6, which show the skate loading device2 viewed from the interior of the skate sharpening machine (compare alsoFIGS. 1, 2 and 4), the loading device 2 according to the invention is sodesigned that it does not give the user access to the interiormechanisms of the skate sharpening machine. The loading device 2according to the invention comprises as a substantially L-shaped doormounted in a matching opening 9 in the front plate 1a. The door 9 hastwo shanks 2a and 2b, which preferably are of equal length, i.e. thedoor has the basic shape of a right angle isosceles triangle. At thepoint of the triangle the door 2 is pivotally journalled on a shaft 10mounted in the frame 1b of the front wall 1a, so that the door can beswung, by pivoting around the axis 10, from the loading position inwhich the skate 3 is located outside the front wall 1a (FIGS. 1 and 5)to the position in which the skate 3 is located inside the skatesharpening machine in the starting position for sharpening (FIGS. 2, 4and 6).

Both shanks 2a and 2b are so designed that they substantially obstructthe loading opening 9 in the respective end positions, i.e. so that theshank 2a substantially closes the opening 9 when the door 2 is in theloading position (FIGS. 1 and 5), and that the opening 9 is kept closedby the shank 2b when the skate 3 is located inside the skate sharpeningmachine (FIGS. 2, 4 and 6). In the shown embodiment bottom portions 11aand 11b respectively of the shanks 2a, 2b keep the opening closed. Thebottom portion 11b is preferably formed by a continuous plate or thelike, whereas the bottom portion 11a is provided with a centrallongitudinal slot 12, into which the skate 3 is to be inserted. Bothbottom portions 11a, 11b preferably also are provided with outstandingedge portions 13a, 13b.

A plate or U-shaped channel beam 14 is mounted beneath the bottomportion 11a at a suitable distance from the same. The plate 14 carriesone or more magnets 15 and one or more sensors 16, such as inductivesensors. The plate 14 further carries a pivot 17, on which the end ofthe piston 18a of a piston/cylinder unit 18 is pivotally journalled. Thecylinder 18b of the unit is pivotally journalled on a stationary framein the machine (at 19), and the unit is driven by a suitable powersource, such as a compressor 20.

The plate 14 serves as an adjustment, clamping and control means when askate blade 3a is inserted into the slot 12 in the bottom portion 11a ofthe door, as is illustrated in FIG. 1. When a skate is correctlyinserted into the slot 12, its blade 3a will be attached by the magnets15, which hold the blade because of their magnetic force. The sensor 16senses the position of the blade and produces an error signal if theposition of the blade 3a is not correct. The other bottom portion 11b ofthe door at the same time serves as a stop for the trailing edge of theskate blade (the skate 3 being moved by gravity towards said bottomportion), so that the skate will be in a well defined rear position inthe slot 12.

The door 2 carrying the skate 3 is moved to the starting position forsharpening (FIG. 6) by operation of (i.e. shortening of) thepiston/cylinder unit 18. The plate 14 will in this position rest on anadjustable stop means such as a set screw 21.

The above described skate loading device 2 according to the inventionhas now fulfilled the duty to safely load the skate into a well definedstarting position inside the skate sharpening machine 1. The verysharpening procedure can, in principle, be performed by means of deviceshaving any suitable design capable of carrying out the sharpeningautomatically and returning the skate 3 to the starting position shownin FIG. 6. The device 2 is then again activated to return the sharpenedskate 3 to the customer, this being done by operation of thepiston/cylinder unit 18 in the opposite direction (i.e. extension of theunit).

In other aspects of the invention it is, however, preferable to use theloading device 2 in combination with a special automatic skatesharpening device shown in the drawings, and in particular incombination with a novel center determination device which will bedescribed below.

The skate sharpening machine shown in the drawings is at its top portionprovided with a slide 22, carried by two rods 23. These rods areparallel with each other and extend between the front and rear sides ofthe machine. The slide 22 hangs on the rods 23 which pass through lugs24 symmetrically provided on the slide. The slide has the basic shape ofan inverted U, having two side pieces 25 defining a central passage 26therebetween, aligned with the skate 3. The movement of the slide 22along the guide rods 23 is controlled steplessly by a suitable motor.

In its resting position the slide 22 is retracted towards the rear ofthe skate sharpening machine (see e.g. FIG. 2). After the loading device2 has moved the skate 3 to the correct starting position for sharpening,as described above, the slide 22 is moved towards the skate 3 in orderto fetch the same by clamping the skate blade 3a between two jaws 27.The jaws 27 have to grip the skate blade 3a at the mid-point thereof (inthe longitudinal direction). In accordance with the invention themid-point determination is performed in very simple manner by means ofonly one position measurement, viz. by detecting the position of theskate 3 and/or of the blade 3a by means of a photocell or some otherposition sensing device 28 provided on the slide 22 on level with theskate/skate blade. When the front edge of the skate breaks the lightbeam in the sensor device 28, this is recorded. As pointed out earlierthe loading device 2 ensures that the trailing edge of the skate blade 3always will have the same position irrespective of the length of theskate/skate blade. This means that the mid-point of the blade will beunambigously determined by the single position measurement made by thephotocell (the mid-point=half the distance between the detected positionand the predetermined position for the rear edge of the skate blade). Acorresponding signal is sent to the drive motor of the slide 22 so as tostop the slide at the mid-point calculated in said manner.

The jaws 27, which are driven by a suitable power source (such ascompressed air from the compressor 20 as is intimated by a compressedair connection 28a in FIG. 2), will now be operated to clamp the skateblade 3a (compare FIG. 4). It is possible to use either two movable jaws27 or one stationary and one movable jaw, the latter alternative oftenbeing preferable for simplicity reasons.

When the skate blade 3a has been clamped between the jaws 27, thedriving motor for slide 22 is reversed, the slide starts moving in theopposite direction, and a grinding wheel 29 is started. The grindingwheel is driven by a suitable motor 30 and is mounted in a pivotingholder or "swinging arm" 31, one end of which is pivotally journalled at32 and the opposite end of which is biased upwards by a weight 33 via acord and pulley wheel 34, 35. Thus, in the free position the grindingwheel 29 is biased by the weight 33 towards an upper position, which isabove the level of the skate blade to be sharpened. When the blade 3a,carried by the slide 22, passes over the grinding wheel 29, it pressesthe wheel 29 downwards (compare the full line and dashed line positionsin FIG. 2), the necessary sharpening force being provided by the weight33. This manner of applying the sharpening force has proven to producevery good sharpening results, and one single sharpening cycle is in mostcases sufficient when using the device according to the invention.

After the sharpening has been completed the slide 22 is returned to theloading device 2, where it delivers the skate 3 by loosening the jaws27. The device 2 now operated to return the sharpened skate to thecustomer, as described above, and the drive motor returns the slide toits resting position.

If the customer has selected sharpening of figure skates (by pressing acorresponding function selector button 6), then the sharpening processis adjusted so as to take into consideration that the blades of figureskates have a toothed front portion which should not be sharpened. Insuch a case the grinding wheel 29 is not started until the toothed toeportion has passed the grinding wheel. Because of the above describeddevice for sensing the length of the skate, it is also simple todetermine the position for starting the grinding wheel 29. It has thusbeen found that the length of the toothed toe portion is relativelyindependent of the skate length, and that minor variations in practicedo not harm the quality of the sharpening. Therefore, the grinding wheelcan be started when the slide has moved a standardized distance form thestarting position corresponding to the edge of the skate.

After the sharpening procedure has been repeated for the second skate,the slide 22 is finally returned to its resting position. Before theskate sharpening machine is ready to be used by the next customer, thegrinding wheel 29 preferably should be dressed to make it possible tomaintain a high sharpening quality and a constant contour of thesharpening. This normally means that the grinding wheel is given acontrolled convex contour, which in turn means that the skate blade willbe hollow-ground.

Thus, the skate sharpening machine according to the invention ispreferably provided with a mechanism 36 for dressing the grinding wheel29, similarly to previously known skate sharpening automates. As bestappears from FIG. 4 the dressing mechanism 36 comprises a diamond 37cooperating with the grinding wheel 29 and supported by a "cradle" 38,which can be rocked to-and-fro around an axis 39, driven by e.g.compressed air from a compressor 20, as is illustrated by compressedpressure valves 40. The cradle 38 normally is in the inactive positionshown in FIG. 4. When dressing the grinding wheel the cradle 38 isrocked the desired number of times (as indicated by the dashedarc-shaped line in FIG. 4) to produce the desired dressing.

A problem to be considered in the dressing process is that the diameterof the grinding wheel diminishes as it is being worn, and this has to becompensated progressively. According to the invention this compensationis achieved by means of a step motor 41 driving a threaded step pin 42,which in turn supports the swinging arm 31 and raises the same a smalldistance each time that the step motor 41 and the step pin 42 are beingrotated. A great advantage of such an arrangement is that one can obtaina very great accuracy in the compensation for the wear of the grindingwheel and that the magnitude of the rise of the swinging arm can beadjusted in a simple manner, e.g. by changing the angular displacementof the step motor 41 in each step and/or by changing the pitch of thestep pin 42. (Normally the compensation is of the order of 10⁻² mm perstep.)

The skate sharpening machine according to the invention is alsoadvantageously provided with further functions. It may especially bementioned that the grinding wheel 29 preferably is water-cooled, as isillustrated by a nozzle 43. The cooling liquid is collected in a tank44. In connection with the cooling nozzle 43, there is preferably asimilarly directed compressed air nozzle for blowing the skate blade 3aclean and dry after the sharpening operation has been completed, forexample while the skate is being returned to the loading device 2.

The skate sharpening machine according to the invention also comprises aprogrammed computer unit 45, which controls and coordinates the variousdetails and functions of the machine depending on program variables,settings and selections of the control and function panel 4, signalsfrom the sensor 16 and the detector 28, possible detectors for sensingthe condition of the various active components, etc. This technique istoday completely conventional to a person skilled in the art, who has nodifficulties in designing and programming the computer unit 45 in asuitable manner with the guidance of the above disclosure, including thedrawings.

It is also obvious to a person skilled in the art that the details ofthe driving and the power sources for the various movable parts of theskate sharpening machine according to the invention can easily bemodified.

The invention is, of course, not intended to be restricted to thespecific embodiments which have been desribed above and shown in thedrawings, but many modifications and variations are possible within thescope of the appended claims.

We claim:
 1. A skate sharpening device comprising an automatic skatesharpening mechanism located inside a protective cover, including askate loading device (2), which is pivotally mounted in an opening (9)in said protective cover (1), so that it can be pivoted between a skateloading position outside said protective cover (1) and a startingposition for sharpening inside said protective cover (1), said skateloading device comprising:(a) gripping means (12, 15) for releasablygripping at least one skate (3) to be sharpened, (b) first obturationmeans (11a) which substantially close said opening (9) in said skateloading position (FIG. 5), and (c) second obturation means (11b) whichsubstantially close said opening (9) in said starting position forsharpening (FIG. 6).
 2. A skate sharpening device according to claim 1wherein the pivot axis (2c) of said skate loading device issubstantially horizontal.
 3. A skate sharpening device according toclaim 1, wherein said skate loading device comprises two shank portions(11a, 11b) making an angle with each other, preferably beingperpendicular to each other, and forming said first and secondobturation means, and in that the pivot axis of said skate loadingdevice substantially passes through the junction (2c) of said two shankportions (11a, 11b).
 4. A skate sharpening device according to claim 2wherein said gripping means comprises a slot (12) in one of said shankportions (11a, 11b) for receiving a skate blade (3a).
 5. A skatesharpening device according to claim 4 wherein one of said shankportions (11b) comprises a stop means for the trailing edge of a skateblade (3) carried by the other of said shank portions (11a), the skateblade being in a defined loading position in said loading device whenits trailing edge contacts said stop means.
 6. A skate sharpening deviceaccording to claim 1 comprising sensor means (16) for detecting that askate (3) is correctly positioned in either said loading position orsaid starting position for sharpening.
 7. A skate sharpening deviceaccording to claim 1 comprising means (27) for catching a skate (3) fromsaid skate loading device (2) when the same is in said starting positionfor sharpening, means (22) for transporting the skate to said skatesharpening mechanism, means (29) for carrying out the sharpeningoperation, and means (22, 27) for returning the sharpened skate to saidstarting position.
 8. A skate sharpening device according to claim 7,wherein said catching means comprises jaw means (27) gripping the skateblade at the mid-portion thereof.
 9. A skate sharpening device accordingto claim 8, comprising position sensing means wherein said sensing meansis a photo detector (28) for detecting the position of the front edge ofthe skate blade in said starting position for sharpening, means forcalculating the mid-point of the skate blade on the basis of saiddetected position and said defined loading position in said loadingdevice, and drive means for actuating said jaw means (27) in responsethereto.
 10. A skate sharpening device according to claim 9, whereinsaid skate sharpening mechanism comprises a slide (22), which is movablein the longitudinal direction of the skate (3), carries said jaw means(27) and said position sensing means (28), and transports the skate (3)from said starting position for sharpening, at least once to-and-froover a sharpening means (29), and back to said starting position.